This refers to the shiny white cap at the end of articulating bones (bones forming joints). The common term would be 'gristle', like the gristle at the end of a chicken bone.

A single surgical treatment of damaged knee cartilage using the patient's own cartilage taken from another part of the knee, ground up during the arthroscopy procedure and sealed into the defect using a fibrin sealant.

Chondromalacia means 'softening of the gristle or joint cartilage' and usually refers to the kneecap (patella). The softening can be felt with a blunt probe during surgery.

Chondropaenia is the process of joint (articular) cartilage loss over time.

Chondroplasty means 'reshaping the joint surface' and refers to simple surgical techniques whereby fibrillated (ragged) and damaged joint surface is cut, scraped, lasered or burred away in the hope that the healthy joint surface will heal over the defect.

Sometimes a knee can make a clicking noise, and this may be painless or accompanied by discomfort or proper pain.

'Clinical' means 'medical'.

A clinical sign is a sign that is evident to a doctor examining a patient.

A clinician is a professional dealing with a patient's medical condition, eg a doctor, nurse, physiotherapist. It is a non-specific term, not implying any particular qualification or branch of medicine.